Digital Video Recording (DVR) technology allows users to record media content such as television programming for later playback upon request. However, conventional DVR technology suffers from several drawbacks. For example, a DVR device must typically be located and maintained in a user's home. Then, the recordings stored on the DVR device are accessible only to the devices to which the DVR device is connected, such as a single television located near the DVR device. Also, the DVR device must have or be able to access digital storage space located in the home that is adequate for storing the user's digital recordings.
Networked Digital Video Recordings (NDVR) allow centralized recordings of media content to be managed for users and delivered to various devices. In an NDVR system, the user may choose to record a live program so that she can consume it later. It could be a program that is on air at the moment, or a program that will be aired in the near future. The operator will store all the files (the multimedia files as well as the metadata) to network storage, and use them to reproduce the same multimedia experience when the user decides to watch at a later time.
NDVR technology has the potential to free users from many of the constraints associated with conventional DVR technology. For instance, recordings may be delivered to a variety of devices such as set top boxes, mobile phones, tablet computers, personal computers, laptops, and smart televisions. These devices may be positioned in a variety of locations and need not be stationary devices in a user's home. Also, with NDVR technology, the user need not own and maintain a device capable of storing the digital content within the home.
A Catch up TV system is very similar to NDVR system, but the operator decides which programs to record, and how long the recorded program should be available to the users for viewing. In either case, if the multimedia service is using the latest HTTP based adaptive streaming technologies (HLS, SS, DASH, HDS, etc.), the same multimedia files are prepared in various different bandwidths and different resolutions. Furthermore, in order to allow the clients to switch among the different representations, the multimedia tracks are composed of many small files. Since all of these files must be stored in order to reproduce the same multimedia viewing experience, it can easily create a bottleneck in the disk input/output (I/O) operations.